# Audio Data API JS Library

### From MozillaWiki

## Contents |

## Introduction

This page is a brainstorming and spec page for a JS library based on the Audio Data API.

http://github.com/corbanbrook/dsp.js

Currently it has js FFT, DFT, Oscillators (sine, square, triangle, saw), envelopes, IIR Filters, Window functions

## Ideas

- < sanchothefat> I'd like to see a similar api to jquery or pjs style eg. a = new Audio(); a.wave('sine');

- extract stuff from bloop, synth, squarewave, etc.

- See existing c++ work at http://www.ricardmarxer.com/loudia/

## DSP.js

The current documentation for DSP.js is as follows:

DSP.js is a comprehensive digital signal processing library for javascript. It includes many functions for signal analysis and generation, including Oscillators(sine, saw, square, triangle), Window functions (Hann, Hamming, etc), Envelopes(ADSR), IIR Filters(lowpass, highpass, bandpass, notch), FFT and DFT transforms.

Modules:

DFT(bufferSize, sampleRate): Discrete Fourier Transform

Usage:

var dft = new DFT(1024, 44100); dft.forward(signal); var spectrum = dft.spectrum;

FFT(bufferSize, sampleRate): Fast Fourier Transform

Usage:

var fft = new FFT(2048, 44100); fft.forward(signal); var spectrum = fft.spectrum;

Oscillator(waveform, frequency, amplitude, bufferSize, sampleRate): Signal Generator

- Sine wave
- Square wave
- Saw wave
- Triangle wave

Usage:

var osc = new Oscillator(SINEWAVE, 440, 1, 2048, 22050); osc.generate(); var signal = osc.signal;

ADSR(attack, decay, sustainLevel, sustain, release, sampleRate): Attack-Decay-Sustain-Release Envelope

Usage:

var envelope = new ADSR(0.01, 0.1, 0.5, 0.1, 0.2, 44100); envelope.process(signal);

IIRFilter(filter, cutoff, sampleRate): Infinite Impulse Response Filters

- Low Pass Filter
- High Pass Filter
- Band Pass Filter
- Notch Filter

Usage:

var filter = IIRFilter(LOWPASS, 200, 44100); filter.process(signal);

## MUSIC.js

MUSIC.js is a library containing functions and data sets to generate notes, scales, arpeggios, chords, phrases and rhythms. MUSIC.js will be highly abstracted, but primarily developed to work with DSP.js.